Rheostat



(12B. REISBACH.

RHEOSTAT.

I APPLICATION FILED APR. 2, 1921- ,4:l4,709. Patented May 2, 1922.

I I 4 SHEETS-SHEET L &'. 1,

49+ 3 4:8 z 1 L L L50 45 INVNTOR.

R1 I B. W

ATTORNEY G. B. REISBACH.

R HEOSTAT. APPLICATION FILED APR- 2', 192].

ATTORNEY saw.

6., s.. REISBACH. RHEOSIAT. v APPLICATION FILED APR- 2, I921 1,414,709;Patented May 2, 1922'.

4 SHEETS-SHEET 3.

- INVEN TOR. Qua km ATTORNEY.-

G. B.- REISBACH.

RHEQSTAT. APPLICATION FILED APR. 2, 1921- 4 SHEETS-SHEET 4.

1,414,709. I Patehted May 2,1922.

Sign 5,

- INVENTOR.

A TTORNEYV UNITED STATES PATENT OFFICE.

GUSTAV B. REISBAGE, 01 MILwAUKEE, WISCONSIN, ASSIGNOB. TO THE CUTLERHAMIMER MFG. 60., O1 KILWAUKEE, WISCOHSIN, A ,COBPORA'IIONQI' WIS-CONSIN.

Specification of Letter: Patent.

Patented May 2,1922.

Application filed April .2, 1921. sem m. 457,9so

To all whom it may concern:

' Be it known that I, GUSTAV B. Rmsnaon, a citizen of. the UnitedStates, residing at Milwaukee, in the county of Milwaukee and State ofWisconsin, have invented new and useful Improvements in Rheostats,ofwhich the following is a full, clear concise, and

exact description, reference belng had to the accompanying drawing,forming a part of this specification.

This invention relates to improvements in the crosshead or similar typedriven by ,a pilot motor under the control of push button stations andhaving means insuring given operations of the rheostat when initiatedbysuch stations .and instantaneously arresting the rheostat uponattainment of the position thcreofselected by the operative.

Another object is to provide a rheostat of the aforesaid character whichwill overcome the difficulties heretofore met with in effectingrelatively small increments of adjustment at the will of the operativeor in other words to provide a suflicient time element whereby theoperative is afforded ample time to operate and release the'selectedpush button without overtravel of the driven element.

Another object is to provide a rheostat of the crosshead pilot motoroperated type hav ing control means adapted to insure de-energization ofthe pilot motor and instantaneousarrest of the crosshead uponmovement-of the latter into a selected position.

Another object is to provide a rheostat of the aforesaid characterwherein provision is made for effecting instantaneous arrest ,of

. the crosshead in a selected position without excessive strains on thedriving means.

Various other obgects and advantages will hereinafter appear.

The invention is susceptible of embodiments in various different formsone of which is illustrated in the accompanying drawings. w i

In the drawings,

' Fig. 1 is a schematicviewof a rheostat I embodying the invention;

Fig. 2 is a diagrammatic view illustrating at; modified arrangement ofthe rheostatconacts; Y

3 is a front elevational view of a' mechamcal embodiment of the rheostatshown 1n Fig. 1; i

4 is a side eli'avational view thereof;

Fig. 5 is an enlarged side elevational view partly in section of thedriving means shown in Fig. 1;-

.Fig. 6 is a. sectional view taken substantially on lines 66 of-Fig. 4;

Flg. 7 is an enlarged vertical 'sectional view of certain of the controlparts shown'in Fi 1; and i Fig. 8 is a plan view of said controlparts.

Referring to Fig. 1, the same illustrates a rheostat of the crossheadpilot motor operated type comprising two series of parallel contacts 1and 2 over which is movable a cross-. head bridging contact 3. Saidcrosshead is operated by a screw shaft 4'driven, by a pilot motor 5through a pinion 6 and gear wheel '7, the latter being operativelyconnected to said screw shaft by a slip pose hereinafter set-forth.

The rheostat is illustrated as controlling the continnit of a circuitillustrated by lines "M and 1' and also. as controlling resistanees R-and R in said circuit. In connection with the resistances R and R, itmay be assumed that' the same are, employed for regulating the speed'ofa motor and that the crosshead is adapted to be'checked in any.

the crosshead in either direction and while said motor may be-of anypreferred type, it has been shown as provided with an-armature A and aseries field windin This clutch 8 for a pur motor is controlled by apair 0 reversing switches 9 and 10 for starting the same and determiningthe direction of operation thereof.

Reversing switches 9 and 10 are. of the double pole type, the same beingbiased to open position and being independently operable by windings 9and 10 respectively. Winding 9 is controlled by a normally open pushbutton 11 through a normally closed limit switch 12 arranged to beopened by crosshead 3 in its upper position while winding 10 iscontrolled by a normally open push button 13 through a normally closedlimit switch 14 arranged to be opened by crosshead 3 in its lowerposition. Winding 10 is also controlled by a normally open relay 15adapted to establish a shunt circuit around push button 13 and saidrelay is controlled by a normally open push button 16 and a normallyclosed limit switch 17 to be opened by crosshead 3 in its lowerposition.

Screw shaft 4is provided with a right hand thread and reversing switch 9provides for operation of motor 5 in a direction whereby screw 4 isrotated in a clockwise direction for upward movement of crosshead 3,while reversing switch 10 provides for operation of the pilot motor inan opposite direction for downward movement of the crossheach While theaforedescribed control means provides for operation of the crosshead ofthe rheostat either direction at will and for 'arrest of the crossheadin any desired position considerable care would have to be exercised inorder to stop the crosshead squarely on the desired contacts, but meanswhich will now. be described insures against stopping of the crossheadexcept when centered on the selected contacts 1 and 2.

- With the contacts 1 and 2 arranged in horizontal alignment as shown inFig. 1, screw 4 is so designed that one complete revolution thereofmoves crosshead 3 a distance correspondingto center spacing of saidcontacts. However, if desired the contacts 1 and 2 can be staggered asshown in Fig. 2 and when the same are so arranged screw 4 is designed sothat one complete revolution thereof moves crosshead' 3 a distance equalto one-half the center to center distance between the contacts or inother words from the position indicated in full lines to the positionindicated in dotted lines. Thus it is apparent that during rotationof'screw 4 crosshead 3 will always assume a centered position on certainof the contacts 1 and 2 as screw 4 passes through a given angularposition and to insure arrest of said screw in such angular position therheostat is provided with a locking device 18 and a commutating device19. 9

Locking device 18 includes a ratchet wheel 20 fixed to shaft 4 andhaving upwardly projecting shoulders 21 and 22 to be engaged y pawls 23and 24 respectively when said shaft is in the aforesaid given angularposition. Pawls 23 and 24 are. pivotally mounted on a shaft 25 and thesame are biased downwardly ried by said shaft. W1 23 is operativelyconnected to the armature of reversing switch 9 through the medium of alever 28 pivotally mounted on shaft 25 and a link 29 pivotallyconnecting the free end of said lever to the upper end of the armatureof reversing switch 9. Lever 28 has a projecting lug 28 for engaging theunder side of pawl 23 and upon closure of reversing switch 9 said lugmoves upwardly to release said pawl from shoulder 21 to permit clockwiserotation of screw 4 for upward movement of crosshead 3 and upon openingof said switch said lug returns to normal position to permit return ofsaid pawl to locking position under the action of spring 27. Pawl 24 issimilarly connected to reversing switch 10 through the mediumof a lever30, pivotally mounted on sliaft'25 and having a lug 30 for engaging pawl24 and a link 31 connecting said lever to the armature of saidswitch.

Closure of reversing switch 10 releases pawl 24 to permitcounter-clockwise rotation of screw 4 for downward movement of crosshead3 and opening of said switch causes return of said pawl to lockingposition. Pawls 23 and 24 are provided with inclined faces 23 and 24respectively, the former face serving to raise pawl 23 when shoulder- 22passes under the same and the latter face serving to raise pawl 24 whenshoulder 21 passes under the same.

Commutating device 19 includes insulated circular contact segments 32and 33 fixed to shaft 4, the former to be engaged by oppositely disposedstationary contact finers 34 and 35 and the latter to be engaged byoppositely disposed stationary contact fingers 36 and 37. Segments 32and 33 are so formed that when the screw shaft 4 is in its lockedposition the contact fingers associated with said segments disengage thesame. As hereinafter setforth the fingers associated with segment 32serve to estab lish amaintaining circuit for winding 10 through anormally open auxiliary switch 38 associated with reversing switch 10while the contact fingers associated with segment 33 serve to establisha maintaining circuit for winding 9 through a normally open auxiliaryswitch 39 associated with reversing switch 9.

v The operation and circuit connections of the aforedescribed controllerwill now be more fully described. As aforestated, the

reversing switches 9 and 10 provide for establishment of reverse powerconnections for pilot motor 5. Closure of reversing switch 9,establishes a power circuit for said motor extending from line L throughthe left hand pole ,of said reversing switch by conductors 45 and 46through armature A from right to left by conductor 47 through the righthand pole of said reversbly coil springs 27 car the series field F andby conductor 50 toing switch by conductors 48 and 49 through line LClosure of reversing switch 10 establishes a power circuit for pilotmotor 5 extending from line L by conductors 51 and 52 through the righthand pole of reversing switch 10 by conductors 53 and -47 througharmature.A from left tofright by conductors 46 and 54 through the lefthand pole of reversing-switch 10 by conductors 55 and 49 throughfield Fand by conductor to line L Assuming that it is desired to move crosshead-3 upwardly push button 11 is depressed to establish an energizingcircuit for winding 9 of reversing switch 9. Such energizing circuitextends from line L by conductor 56 through windin 9 by conductor 57through limit switch 12 y conductor 58 through push button 11 and byconductors 59 and 60 to line L As before set forth, upon response ofswitch 9 pilot motor 5 operates in a direction for effecting clockwiserotation of screw 4- and saic switch in responding releases pawl 23 fromshoulder 21 to permit rotation of said screw in such direction.Crosshead 3 moves upwardly subject to opening of push button 11 andassuming that said push button is'released when crosshead 3 is incentered relation with respect to contacts 1 and 2 reversing switch 9immediately opens and causes instantaneous arrest of screw shaft 4 bymovement of vpawl 23 into engagemen't with shoulder 21. It-is apparentthat upon arrest of screw shaft 4 by pawl 23 th'e motor 5 will tend tocoast and slip clutch 8 then acts to friotionally overcome the acquiredmomentum of motor 5 to thereby prevent excessive strains on the drivingmeans. Assuming that push button 11 is released while crosshead 3 is outof centered relation with contacts 1 and .2, segment 33 establishes ashunt maintain ng circuit around push button 11 for winding 9 whichextends from line L by conductor 56 through winding 9* by conductors 57and 61 through auxiliary switch 39 by conductor 62 through contactfinger 36,

segment 33, contact finger 37 and by, conductors 63, 64 and to line LUpon movement of crosshead 3 ihto centered relation with contacts, 1 and2 contactsegment 33 moves out of engagement with contact finger 37 tointerrupt the aforedescribed maintaining circuit and reversing switch 9then opens to arrest crosshead 3 in the manner above set forth. Uponopening of reversing switch 9, auxiliary switch 39 opens to preventenergization 6f reversing switch 9 through segment 33 and itscooperatingfingers during counter-clockwise rotation of screw shaft 4. If pushbutton 11 is maintained depressed until crosshead 3 moves into its upperlimit, limit switch 12 switch 10 thereupon closes to energize motor 5for counterclockwise rotation of screw shaft 4 and upon closure of saidswitch pawl 24 is released from shoulder 22 to permitsuch rotation ofthe screw. If crosshead 3 is 'in centered relation with contacts 1 and 2at the instant push button 13 is released, winding 10 is immediatelyde-energized to cause reversing switch 10 to open, whereupon pawl 24engages shoulder 22 to lock screw shaft 4 against further rotation andslip clutch 8 acts to overcome the acquired momentum of pilot motor 5.If push button 13 is released while crosshead 3 is out of centeredrelation with contacts 1 and 2, contact segment 32 and its associatedfingers establishes a maintaining circuit around push button 13 forwinding 10, said circuit extending from line L through winding 10 asalready traced by conductors 66 and 69 through auxiliary switch 38 byconductor 70 through contact finger 34, segment 32 and contact finger 35and'by'conductors 63, 64 and 60 to line L When crosshead 3 moves intocentered relation with contacts 1 and 2, segment 32 moves out ofengagement with finger 35 to interrupt said maintaining circuit and.reversing switch 10 opens to arrest screw 4 inthe manner above noted.Upon opening of reversing switch 10, auxiliary switch 38 opens to insureagainst subsequent energization of winding 10 by commutating device 19.If push button 13 is maintained depressed until crosshead 3 moves intoits lower position, limit switch 14 is opened by said crosshead tointerrupt the aforedescribed energizing circuit for winding 10;

If crosshead 3 is raised andit is desired to return the same directly to06:1 position push button 16 is depressed to energize relay 15 through acircuit extending from line L by conductors51 and 71 through limitswitch 17 by conductor 72 through winding 15 of relay 15 by conductor 73through push button 16 and by conductor 60 to line L In responding,relay l5 establishes a shunt maintaining circuit for winding 15 aroundpush button 16 through contacts 15 and contacts 15 thereof vestablishingan energigiag circuit for winding 10 of reversing switch 10, extendingfrom line L through winding 10 and limit switch 14 as already traced; by

conductors 67 and 74 through the contacts 15 and by conductors 68, 64and 60 to line L Relay 15 remains closed to maintain winding 10energized until crosshead 3 moves into its lower limit whereupon limitswitch l7 is opened by said crosshead to interrupt the energizingcircuit of winding 15.

Referring to Figs. 3 to 8 inclusive, wherein is illustrated a mechanicalembodiment of the aforedescribed controller, the various parts of therheostat are mounted upon an insulating panel 75. Contacts 1 and 2 aresupported by insulating panels 76 and 77 arranged in a parallel relationand mounted at rightvangles to insulating panel 75. Panels 76 and 77 aresupported at their upper ends by a bracket 78 and at their lower ends bya bracket 7 9,-said brackets being secured .to the face of panel 75.'Crosshead 3 comprises a frame 80 provided with the usual traveling nut81 and said bracket has mounted on opposite sides thereof a plurality ofcontact shoes 82, said shoes being of a conventional type. As isunderstood, the upper shoes 82 serve to control the amount of resistanceincluded in circuit and the aforeclescribed centering means is arrangedto effect centering of said upper contacts with respect to stationarycontacts 1 and 2. Frame 80 is also provided with additional contactshoes on the rear thereof for engaging contacts mounted on the face ofpanel 75, the latter contacts being provided for controlling the fieldcircuit of a motor.

Screw shaft 4 is rotatably mounted in bearings 83 and 84. carried bybrackets 78 and 79 respectively and gear wheel 7 is rotatably mounted onsaid screw shaft adjacent the lower end thereof between friction rings85-. As best illustrated in Fig. 5, the lower friction ring 85 rests ona flange 86 secured to the lower end of screw shaft 4 and the upperfriction ring has a flanged member 87 bearin thereon the latter beingpressed downwar ly by a spring 88. Pilot motor 5 is secured to the faceof panel 75 and the reversing switches9 and 10 are of a conventionaltype and are arranged on opposite sides of said motor. As bestillustrated in Figs. 3', 4 and 6, bracket 79 is provided with downwardlyprojecting. lugs 89 for supporting shaft 25 of the locking means.

Commutating device 19 is arranged'above bracket 79 and as shown in Fig.7, said device includes a hub 90 arranged to be keyed to screw shaft 4,said hub carrying insulating discs 91 and 92 on opposite ends thereofwhich are secured to contact segments 32 and 33 to support the latter.As shown in Fig. 8 contact fingers 34 to 37 are each provided with asupporting bracket 93 secured to panel 75 and each of said fingers isse-- ventional type and as shown in Fig. 4 the same are mounted on therear of panel 75 and each is provided with a reciprocablc operatingmember 95 extending through an opening in said panel. The operatingmembers 95 are biased to move towards the left and are movable towardsthe right to open their respective switches by rollers carried by frame80, one of said rollers being illustrated at 96 in Fig. 4.

\V hat I claim is new and desire to secure by Letters Patent is:

1. In a device of the character set forth, in combination, a poweroperated member having different positions of rest, control means foreffecting operation of said member in opposite directions, meansassociated with said formermeans insuring against stopping of saidmember in positions other than the aforesaid positions said latter.means including means for positively locking said member in a selectedposition.

2, In a device of the character set forth, in combination, a poweroperated member movable in opposite directions and having 90 a pluralityof positions of rest, control means therefor providing for movementthereof ineither direction and insuring against arrest thereof inpositions other than the aforesaid positions, said control meansincluding a '95 positive locking device adapted to act automatically toarrest said member in a selected position.

3. In a controlling device, in combination, a plurality of contacts, apower oper- 100 ated member movable into engagement with any selectedone of the same, and controlling means for said member insuringsubstantial centering thereof with respect to the selected contact, saidcontrol means including a de vice for positively locking said member insubstantially centered relation with respect to the selected contact.

4. Ina controlling device in combination,

a plurality of contacts,'a power operated 0 member movable intoengagement with any one of the same, control means for said member toeffect movement thereof in opposite directions, and means associatedwith said control means, including a positive locking connected to saidswitches for locking said member against movement beyond the selectedcontact.

6. In a controlling device in combination, a plurality of contacts, anelectromag netically operated member movable into engagement with anyone of the same, reversing switches operable selectively to effectmovement of said member in opposite directions, selective control meansfor i said switches including means for preventing topping of saidmember in positions between said contacts and a locking devicemechanically connected to said reversing switches for arresting saidmember-to insure substantial centering thereof with respect to aselected contact. I

7. In a controlling device in combination, a plurality of contacts, a.contact member movable into engagement with any one of the same, areversible electric driving motor for eifecting operation of said memberin opposite directions, control means for'said motor, means associatedwith said control means for insuring de-energization of said motor andsimultaneous arrest of said memher when the latter is brought intocentered relation with a selected-contact and means for frictionallyovercoming the acquired momentum of said motor upon arrest of saidmember. I

8. In a controlling device, in combination, a plurality of contacts, acontactmember movable in opposite directions into engagement with anyone of the same, an adjusting screw for said member, a reversibleelectric driving motor, a driving connection between said motor and saidscrew including a slip clutch, control means for said motor, and meansassociated with said control means for insuring interruption of thepower cir-. cult of said motor and simultaneous lock-.

an electric driving motor therefor, sepa rately operable electroresponsive switches for starting said motor in opposite direction forreverse adjustments of said rheo-' stat, selective control means forsaid switches to direct operation of said motor and adjust mentof saidrheostat, means associated with -.'said rheostat to insure energizationof said switches independently of said former means i when said'rheostatis in any other than predetermined positions of rest and to insurede-energization of said switches in such positions of rest, and meansactuated by said switches upon opening thereof forlocking said rheostatin said positions of 'rest.

10. In combination, an, adjustable rheoan, electric driving'motortherefor, separately operable electro-resp'onsive switches rectoperation of said motor and adjustment of said rheostat, meansassociated with" said rheostat to insure ,energization of said switchesindependently of said directing means when said rheostat is in any otherthan predetermined positions of rest and to insure de-energization ofsaid switches in such positions of rest, means actuated by said switchesupon de-energization thereof for locking said rheostat in said positionsof rest, and means for frictionally overcoming the acquired momentum ofsaidmotor upon locking of said rheostat.

11. In a device of the character set forth in combination, a contactmember movable in opposite directions to any oneof a plurality ofpositions of rest, an operatingscrew therefor adapted during eachrevolution to move said member to a degreecorresponding tothe distancebetweensuch positions,

a reversibleelectric driving motor for said in opposite directions toany one of a'plura-lity of positions of rest, an operating screwtherefor adapted during each revolution to move said member to a degreecorresponding to the distance between such positions, a reversibleelectric driving motor for said screw, control means for said motor foreffecting operation ihereofin either direction and for insuring againstde-energization thereof until said-member moves into the selectedposition of rest, means associated with said control means forpositively locking said screw for arrest of said member 1n the selectedposition, and means for frictionally overcoming the acquired momentum ofsaid motor upon locking of said'screw.

'13. In a rheostat, in combination, a contact member movable in oppositedirections to any one of a plurality of positions of rest, -'anoperating screw therefor adapted during each'grevolution to move saidmember to a degree corresponding to the distance between. jsuchpositions, an electric driving motor for said screw, control means forsaid motor including a pair of reversing switches operable selectivelyto efl'ect ad3ustment of said contact member in opposite directions,means associated with said control means for insuring against opening ofsaid reversing switches except upon movement of said member into aselected position of rest, and locking means directly connected to saidreversing switches and adapted upon opening of the latter to lock saidshaft in a predetermined angular position to prevent movement of saidmember beyond the selected position.

14. In a rheostat, in combination, a contact member movable in oppositedirections to any one of a plurality of positions of rest, an operatingscrew therefor adapted during each revolution to move said crosshead toa degree corresponding to the distance between such positions, a drivingmotor, a driving connection between said motor and said screw includinga slip clutch, a pair of reversing switches for said motor operableselectively to move said crosshead into a selected position of rest, andlocking means associated with said reversing switches for arresting saidscrew upon movement of said crosshead into a selected position, saidslip clutch acting upon arrest of said screw to overcome the acquiredmomentum of said motor.

15.In a rheostat, in combination, a contact member movable in oppositedirections to any one of a plurality of positions of rest, an operatingscrew therefor adapted during each revolution to move said member to adegree corresponding to the distance between such positions, a drivingmotor, a driving connection between said motor and said screw includinga slip clutch, control means for said motor including a pair ofreverslng switches operable selectively to establish reverse powerconnections for said motor for adjustment of said contact memher 111opposite directions, means for looking said screw in a given angularposition for arrest of said contact member in the selected position,said means including a ratchet member secured to said screw andcooperating pawls respectively connected to said reversing switches,each of the latter being releasable from said ratchet wheel upon closureof its respective switch and being adapted to lock said screw againstmovement upon opening of said switch.

16. In a rheostat, in combination, a movable contact element having aplurality of positions of'rest, an operating screw therefor adaptedduring each revolution to move said member to a degree corresponding tothe distance between said positions, a driving motor, an operatingconnection between said screw and said driving motor including a slipclutch, control means for said motor adapted to effect operation thereof in opposite directions, and means as sociated with said control meansfor arresting said screw in a given angular position for arrest of saidelement, and for simultaneously de-energizing said motor, said slipclutch acting upon arrest of said screw to overcome the acquiredmomentum of said motor.

17. In a rheostat, in combination, a movable contact element' having aplurality of positions of rest, an operating screw therefor, a drivingmotor for said screw, a pair of reversing switches for establishingreverse power connections for said motor, control means for saidswitches, including means for insuring opening of said reversingswitches upon movement of said contact element in opposite directions togiven limits, and means insuring against opening of said reversingswitches upon positioning of said contact element between said positionsof rest and provding for positive locking of said screw in a givenangular position to insure against overtravel of said member beyond theselected position.

18. In a rheostat, in combination, a power operated contact elementhaving a plurality of definite positions of rest, control means fordirecting adjustment of said element from one position to another andrequiring manual retention of a part thereof to effect continuousoperation of said element through any of said positions, said meansincluding means insuring movement of said element into one of saiddefinite positions upon release of said manually retained part in anyintermediate position of said element and additional control meansacting upon momentary operation of a part thereof to effect continuousoperation of said element through a number of said definite positions toanother of said positions.

In witness whereof, I have hereunto subscribed my name.

GUSTAV B. REISBACH.

